Unless you want 'Registered Users' to comment on your site, I don't think its required. Also, if you have any restrictions on certain part of the site or downloads or something like that.
Apache Version 2.2.14 (Unix) | PHP Version 5.2.12 | MySQL Version 5.1.43-log | Architecture x86_64 | OS Linux | Joomla Version 1.5.20 | pHpBB v3.0.7-PL1 | Firefox v3.6.8 | Internet Explorer 8 |
If you Bridge Joomla with pHpBB, then I don't think you require users to register on your main portal (Joomla). So, i guess my previous statement contradicts with this one
Edit: Sorry for creating confusion. I guess i should have let the experts talk
Apache Version 2.2.14 (Unix) | PHP Version 5.2.12 | MySQL Version 5.1.43-log | Architecture x86_64 | OS Linux | Joomla Version 1.5.20 | pHpBB v3.0.7-PL1 | Firefox v3.6.8 | Internet Explorer 8 |