A number of iOS applications have been updated following the release of the new iPad. While most of the software updates quickly approved by Apple have focused on Retina graphics, others that have come out in the past few days have brought new important functionalities as well.

PDF Expert, our favorite app to read and manage PDFs on the iPad, adds Retina graphics and document thumbnails in its new 4.0 version. On the new iPad, graphics are shaper and more detailed, but more importantly text is crisper and more readable. The new thumbnail-based interface makes for a more visual presentation and intuitive file browsing, although support for drag & drop could be improved (I’d like to be able to create folders by dropping a file on top of another, like on the Home screen). PDF Expert 4.0 also supports PDF portfolios, attachments, and embedded media.

ReaderX has improved a lot since my original review. The app now comes with more fonts, more options, a revised preview popover, improved scrolling, and better sharing. The wallpaper concept makes a lot more sense on the iPad’s Retina display, as it makes it easy to set smaller fonts, while maintaining readability and detail. Give it a try again.

OneEdit is an app I use on my iPad to quickly resize multiple photos at once and save them back to the Camera Roll. The app doesn’t support Retina graphics yet on the new iPad, but the issue will likely go unnoticed (except for the icon) as the app uses a lot of native UI elements that Apple is already providing at Retina size. OneEdit 1.8 (the app is sold in separate versions for iPhone and iPad) enhances the batch-processing features of the app with support for individual photos from Dropbox, upload to WebDAV, and possibility to resize images based on scale. I particularly like OneEdit’s approach to image editing with separate sources/tasks/output processes that makes it easy and clear for me to select images, act on them, and save them somewhere else. OneEdit is also pretty powerful with tons of other options I don’t use, so make sure to check out the app’s full description on the App Store.

Watchlater keeps on being one of the best options to save videos from the web for later by adding a new design and more sharing options to version 2.5. Functionality-wise the app is mostly unchanged from my original review, but the UI is much better and collaborating with friends on playlists is a great idea.

Other minor updates have been released on the App Store as well: Note & Share added fixes and new iPad compatibility; LogMeIn Ignition added Retina graphics; Path started hashing user data with version 2.1.1; Alien Blue for iPad added a new gesture to load Reddit comments.

Make sure to check out the Great apps for the new iPad App Store section for a comprehensive list of software updates released in the past weeks.

As noted by MacRumors, Apple has created a new Catalogs category on the App Store, moving a number of existing apps into it. The category looks interesting for a number of reasons: first off, Apple doesn’t just create new App Store categories, which are prominently featured on iTunes, leaving them empty as Catalogs looks when browsed from its direct URL right now. Second, whilst both iPhone and iPad apps have been moved into Catalogs, the empty App Store listing page reports “iPad Catalogs” – this might as well hint at catalogs, as in shopping guides, being part of an announcement on stage tomorrow, or perhaps some demo time.

Several existing apps have already been placed into the Catalogs category, including Catalog Spree (pictured above), SkyMall, MTG Merchant and more. These apps have long existed in the App Store and have now been recategorized to “Catalogs”. The apps had previously been listed under the Lifestyle and Utility sections of the App Store.

Interestingly enough, Google’s own Catalogs app for iOS has received the new category treatment, while IKEA’s app is still listed under Lifestyle. The new Catalogs category can be accessed here, albeit opening the link in a browser returns an empty itunes.com webpage.

Whilst a new category isn’t necessarily related to the next iPad, the fact that Catalogs went live ahead of the scheduled event and that it appears to not be completely developed seems to suggest that might be more coming soon. Tune in tomorrow at 9:30 AM PST for our Apple event liveblog.

According to MG Siegler at TechCrunch, Apple has acquired Chomp, app search and recommendation engine that has an iPhone app available in the App Store. Siegler reports that the Chomp team and product will be transitioned over to Apple, although details of the deal aren’t clear:

My understanding is that such deals will remain intact for now but are likely to end once the Chomp team and product transitions over to Apple. The same is likely true for Chomp’s stand-alone products.

I haven’t been able to learn the exact terms of the deal, but I hear that all the investors should be very pleased with the outcome. This is not a cheap “acqui-hire”, Apple has bought the Chomp team and technology and plans to use both to completely revamp App Store search and recommendations, I hear.

With Apple’s Tim Cook famously saying he’s not religious about holding or not holding the cash (nearly $100 billion) at Apple’s disposal, the acquisition of Chomp should be a clear sign of the company’s willingness to invest in talent and technologies from startups that have proved to care about quality of their products. Chomp in particular is an interesting choice for Apple, as it might signal important changes coming relatively soon to the App Store, especially on the side of discovery of apps with recommendations targeting a user’s tastes and behaviors. With over 700,000 apps available (per AppShopper) and thousands getting approved every day, the issue with discovery is a real one: most developers struggle to get their apps noticed and the best chance for popularity still remains Apple’s own feature in the App Store’s homepage with the “App of the week” and “New & Noteworthy” sections. Furthermore, the existing App Store infrastructure doesn’t have integrated sharing features for Twitter and Facebook, which Chomp has.

It’s obviously not clear what Apple has in store for Chomp yet, but here’s a couple of wild guesses based on the app’s existing functionalities:

Improve app discovery learning what an app does, rather than just its name. Currently, Apple seems to be basing its algorithm for discovery (part available in the Genius UI, part in iTunes under an app’s description) on categories and “what other customers also bought”. Chomp is capable of learning an app’s core functions, and find similar or complimentary apps.

Build sharing of apps for Twitter and Facebook right within the App Store. This would be a nice feature in iOS 6 – alongside a mobile wish list.

Improve search with suggestions, tags, and a cleaner layout similar to what Chomp already does.

Let App Store users create profiles and revamp the whole review system, as developers have been asking for years now. The profile option would be an interesting possibility, and it could easily work in conjunction with Ping, which has failed to gain traction. This has also been experimented by other apps that have tried to compete in the app recommendation space in the past years.

As with the recent Anobit acquisition, it’s likely Apple will confirm the acquisition of Chomp soon. It will be interesting to see if and how Chomp’s technologies will be integrated with a future version of the App Store, which keeps on growing at a tremendous pace but needs a better system to discover apps and filter out less important results.

Update: Apple has confirmed the acquisition to AllThingsD without providing further details on how the service will be integrated with the App Store.