Not sure what you mean. Are you asking about the number of accounts in a bitcoind wallet or the number of peer connections? As far as I know, bitcoind maintains a single local wallet but the wallet can have multiple accounts in it. – ScripterRon – 2013-12-26T15:01:30.253

oh? I thought bitcoind permits the creation of multiple wallets? If I develop my own online wallet system (each user can create his/her own wallet) does it then imply I create one wallet and then accounts within the wallet for every user on my system? – user11286 – 2013-12-26T15:19:06.053

That's my understanding. Or you could maintain the user accounts in your own database and only use the bitcoind wallet when you send or receive coins to external users. This would allow you to move funds among your users without involving blockchain transactions. Either method gives you control of the user funds since you control either the bitcoind wallet or your database. Unless the private keys are stored on the user systems, in which case I'm not sure what service you are providing. – ScripterRon – 2013-12-26T18:18:02.093

Is there a limit on the number of accounts one can have per wallet? – user11286 – 2013-12-26T20:51:12.480

I don't know. But I expect performance will degrade quickly as the number of accounts increases. It would be better to handle a large number of accounts outside of bitcoind using database software. – ScripterRon – 2013-12-27T00:53:37.983