Comparison of e-book formats

I am deeply interested in ebook formats and their natural diversity. Thus, I really liked this article at wikipedia, which discusses quite a few formats in some adequate detail.

Evolution of mobile web standards

I find this image at wikipedia on the evolution of mobile web standards really instructive.

Html_escape, a.k.a h doesn't escape single quotes

One should always use double quotes for specifying html attributes, if the attribute content comes from outside, as the html_escape helper escapes only double quotes. In other words:

HTML_ESCAPE = { '&' => '&', '>' => '>', '<' => '<', '"' => '"' }

Digest::MD5.hexdigest produces wrong hash in Rails

I forgot to require the file 'digest/md5', and instead of barking out loud, rails just gave me some wrong hash value. So, shouldn't forget this line, if using MD5:

require 'digest/md5'