This:
"Tue Jan 12 21:33:28 +0000 2010"
was returned from Twitter's API. The rest are fairly obvious, but what does +0000 refer to? Is it some type of denotation of a timezone?
+0000
is an HHMM
offset from UTC/GMT, and in this case the time you're getting back is exactly UTC.
Note that this doesn't exactly map to a "geographical" time zone, since daylight savings time may change the offset. For example, Sweden is +0100 in the winter and +0200 in summer.