It seems Keybase have been overwhelmed by fake accounts trying to get a share of this huge airdrop. The last distribution will be next week.
I cannot complain as I have done pretty well from it. We are talking about $16m overall across many thousands of users. I have given away some Stellar Lumens and used some to buy Steem. Free money is a very rare thing and any offer will be abused. I would hope Keybase gained a lot of legitimate users who were actually interested in the services they offer. You get some good encrypted communication tools, cloud storage and the ability to verify you control various on-line accounts. I will continue to use these.