I've been working for a few years on creating an archive of every version of every Android app Hatena has created. I am still missing some versions as I was not able to get them into my Google Play library, but it's fairly complete.
Versions Package ID 279 com.hatena.android.bookmark 39 jp.ne.hatena.blog 18 com.hatena.android.space 13 com.hatena.android.accounts 10 com.hatena.android.monolith 9 com.hatena.android.fotolife 6 com.hatena.android.coco 1 com.hatena.android.bkuma.girls
I am missing several versions of B!KUMAガールズ but I believe I have all of the rest.
I also have several apps under the jp.ne.hatena.neetlabo namespace; I don't really know if I should include them or remove them, but I have them anyway. I haven't been able to find out if they were made at Hatena or not.
Eventually I want to archive all versions of Hatena Firefox extensions and Chrome extensions, but I'm struggling a bit to properly organize and version them; for Firefox, there doesn't seem to be a proper namespace or app id system that I can pull from the .xpi; for Chrome, .crx seems to be a custom .zip format that takes a lot of extra work to pull an extension ID from.
Finally, I have had no luck getting copies of .ipa files for the Hatena iOS apps, e.g. LGTM, Blog, Bookmark, etc. I might be able to do so eventually, but I'm not super hopeful at present.