The kanji information on this site has been downloaded from the KanjiDict project - you can see full details on their website.
Stroke Count
How many strokes of the brush it takes to write the Kanji. Some Japanese Kanji dictionaries are organised by stroke count.
Japanese children are taught to write their Kanji strokes in a prescribed order.
Frequency
The top few thousand Kanji have been ranked by frequency based on how often they appear in newspaper articles.
The top ranked kanji is number 1 and so on. Unranked kanji don't appear in newspapers very often
More details coming soon. In the meantime for a full description of the data fields visit the KanjiDict website.
There are loads of Kanji resources online - I like Kanji Damage