I'm not a recluse technically(i do leave the house when i need it), but i can understand the mentality behind it. Socialization is not a walk in the park, its time-consuming and requires serious commitment/effort(there plenty of "difficult" people) - while having people on the internet as the social group doesn't place a burden on the person at all(he can leave or change the group any time without much investment). Avoiding unnecessary social interactions reduces stress and allows more time to be dedicated to own pursuits, at some cost of appearing more awkward/maladaptive within social circles. A price many are willing to pay: the problem is that social interactions are unavoidable long-term and lead to low social status as established social circles create a psychological entrance barrier of shared expirience/in-jokes/culture which evolves with them(like e.g. insulated internet communities) where any faux-pas disqualifies one from being a member.