A person can necessarily only be a potential lolcow with a public Internet presence broadcasting their personality.
A person with an online presence is most likely to, at least for the main part, maintain that presence themselves (rather than have it run by another party).
A person who maintains a public Internet presence broadcasting themselves to the world is likely to be quite online and, at least to some degree, self-important.
The type of strange person considered to be a potential lolcow is likely to have elevated negative character traits.
Being very online and self-important are (broadly, negative) character traits.
Potential lolcows are likely to be extremely online and a fair bit more narcissistic or self-important than the average Internet user.
An extremely online and self-important person is likely to be aware of any place making mention of them online due to their having easy access to online sources (they are extremely online) and a high degree of interest in discussion centred around their person (they are self-important).
Discussion perceived as negative about a self-important person is likely to have a negative effect on them.
Negative aspects of a person's life are likely to be broadcast to the Internet if this person is self-important and extremely online.
A potential lolcow is likely to broadcast negative aspects of their life.
Gossip-focussed discussion forums are more likely to increase activity on a subject over that subject experiencing negative effects, rather than improving over time or experiencing no change at all, assuming these effects are broadcast.
A lolcow who suffers negative effects from perceiving discussion centred on them as negatively focussed will broadcast these negative effects, which will in turn generate further discussion.
The only limit to this cycle is the limit of the lolcow's obliviousness to their own activities being perceived as ridiculous.