PCWorld reports that Google has withdrawn the Grooveshark app from Android Market, in what was suggested to be the company “cleaning up” its app catalogue by removing questionable apps. Grooveshark is an app which links to a music sharing site where customers upload content and, as with high-profile predecessors such as Napster and Limewire, the company has fallen foul of many copyright holders. It was noted that Apple had pulled the app from its iOS App Store, reportedly after pressure from record labels.

It was also noted that Google is believed to have its own music app in the works. According to various reports, some consumers have seen an updated Music app available through a “Test Market” app which has appeared on some Android devices, believed to be intended for developers – but which somehow made it to some consumer devices. The updated Music is said to resemble the software included in the Honeycomb variant of Android for tablets, and link to a cloud-based music service.

Separately, GigaOM reported that Google has “apparently gone ahead and started factoring in the stickiness of apps in its Android Market rankings,” meaning the titles which have the most long-term success with customers are being positioned more prominently in the results. It was noted that in a short period of time, a number of apps saw their rankings improve dramatically, while others dropped. This was seen as an indication that the company had altered its algorithms to include additional features although – as with Google’s search practices, this is not something the company openly details.

According to GigaOM, Geoff Cook, CEO of myYearbook – which saw some of its apps rise and fall following the revamp – noted that a ranking based on usage is less easy to manipulate than one based on installs, which can be manipulated by heavy advertising spends and price cuts. The report also suggests that it may be harder for fresh applications to “break out” and gain visibility, but that a focus on usage rather than pure download numbers may benefit the industry in the long-run.