Nick linking
From BoyWiki
Nick linking is revealing that two or more nicknames are used by the same person. The nicknames need not be used in the same context (for example, the same message board or chat room).
Sometimes an individual using online communication services wishes to use several nicknames (see Nickname for common reasons). Often this is done in the open, the poster linking the nicknames at the outset; but probably most often it is done secretly. When this is the case, purposely linking the two nicknames is considered a hostile act akin to (or even facilitating) outing. Involuntary nick linking is also considered dangerous.