Back when Gmail was invite-only, most people used Hotmail or Yahoo Mail, which would offer a base level of (I think) about 50-100MB of storage at the time. If you wanted more storage; you'd have to pay for your email service - an idea I don't think anyone born past 2000 has even heard of.
Gmail came along, and suddenly offers us 1 GB of free storage, for free. This was around a quarter the size of some people's hard drives at this point.
Of course we didn't care if there was no support!
Are you kidding? I don't think Hotmail had support, either - (maybe I'm wrong?) - even if you paid for it; but here Google was offering a substantial value for anyone using any other existing mainstream email service, immediately.
They even had STMP and IMAP support, meaning you could use whatever client you preferred. Back in the day most people used computer-side email clients and had local backups of emails anyway - so if one went missing from Google's side it wouldn't be so bad.
There's a reason Gmail is still one of Google's strongest and unusually longest-lasting product of Google's. There's less reason now - but my God, when it was introduced it was an honest-to-God mindfuck as to how they were offering such a large amount of space and features for nothing.
The selling feature of Gmail was "Now you can keep all your mail and have a permanent searchable history of all your electronic communication".
Of course, now we all understand that they were harvesting all the personal data this gave them access to, in order to monetize it, and sell access to it to anyone who would write them a check.
And then we found out that this information was so valuable, and in such a concentrated place, that the CIA placed fiber taps on Google’s data center drops.
"In-Q-Tel scouts the global market for commercially focused technologies with the potential to contribute to national security." - Source: iqt.org