One more thing of interest that I noticed about Facebook. Companies that used to use place ads via Google and also advertise on Forums have found out that they too can create Facebook groups to engage with their customers. For example, an automotive parts suppliers started opening Chevrolet "fan sites" on Facebook in order to market to Cruze, Camaro, etc. owners directly. Pretty clever.
Facebook has built a great mousetrap. In under one minute, you can build a Facebook group and add a lot of people too it to create an instant community. And all of this without the expense of forum software and a host. We've leaned heavily into creating more Facebook groups rather than forums because not only is the expense much less, you have a much wider audience to gain members from. Moreover, people can belong to dozens of groups on Facebook at one time and thus receive all kinds of updates at a one stop shop. Forums still certainly have a place for more niche discussion where different categories are important, however, I think that IPS has not done a good enough job with their software in the past several years. It's interesting that big forum companies are not choosing IPB, even those migrating away from VB. I'm sticking with IPB for right now, but the pace of change has been agonizingly slow and that just doesn't help with situation.
Facebook has really built a great mousetrap and their ability to create a group so easily changed the dynamics of the game - From what I've been reading, IPB 4.0 is a great framework, however, it's also where IPB should have been over a year ago, so this might be more of a catch up to the competition type of release. 4.0 seems to be coming along nicely, so thanks to the IPS develop team as I look forward to it. While IPB is my favorite, what's interesting is how major forum publication houses don't use it like they do the competition. With VB reportedly in chaos (and I don't know if that's factually correct), a few big players moved to Xenforo. Personally, I find that IPB is on this desire to run such a clean looking site that it mutes the ability for forum users to engage and participate more. Maybe 4.0 will change this and I think that right now @Kevin Carwile understands this the most and he's developing some interesting stuff.
Having a DMCA notice on your site is a good start, however, it doesn't offer total legal protection unless you also have a registered agent on file with the U.S. Gov't. If a party wishes to file a complaint against you and you do not have a registered agent listed, you DMCA statement might not be effective. Generally, if someone has a complaint, they will contact you through a contact link on your site or look your domain contact information up. However, legally, you need to have an agent (it can be you) on file to claim safe harbor.
Here's what concerns me about these e-mail notifications - if people with yahoo, gmail, aol, outlook, etc. accounts cannot stop these e-mails and they become burdensome, they may be prone to simply marking them as spam. Should that happen and your host turns off your ability to send out e-mails and new user validations, then your community is dead.