[dreamweapon]

In German: E-Mail, URL, CD-ROM, and Jeans are usually feminine, for example.

Basically, whenever a noun (or the core of a compound noun) has a direct (or close) translation to a frequently used noun in German, then it's quite common for its gender to "bleed" over into the English loanword.

So in the examples above, Mail → Post, URL → Verbindung, CD-ROM → Platte, Jeans → Hose, etc.