Too sad story.
en – Android Fragmentation Visualized
http://opensignal.com/reports/fragmentation-2013/
ja – Android開発者が絶望しそうな現在の利用状況まとめレポート
http://www.ideaxidea.com/archives/2013/08/opensignal_report.html
About twitter
These maybe help you that develop twitter app.
en – Create Twitter Button
https://twitter.com/about/resources/buttons#hashtag
en – Android Twitter oAuth Connect Tutorial
http://www.androidhive.info/2012/09/android-twitter-oauth-connect-tutorial/
ja – WebView使わずに、twitter4j のOAuth認証
http://androidadvent.blog.shinobi.jp/2012/twitter4j-oauth
Basics of web page
These maybe help you that create standard web pages.
en – 30 HTML Best Practices for Beginners
http://net.tutsplus.com/tutorials/html-css-techniques/30-html-best-practices-for-beginners/
en – 20 HTML Best Practices You Should Follow
http://sixrevisions.com/web-standards/20-html-best-practices-you-should-follow/
en – A Detailed Look at the 960 CSS Framework
http://net.tutsplus.com/articles/news/a-detailed-look-at-the-960-css-framework/
Check your target browser if you want using html5 full functions.
ja – HTML5 browser spec checking tool
http://spec.nttdocomo.co.jp/spbss/index.html