2000 characters, assuming a 1 byte encoding like ASCII or ANSII is ~2kb per user. 1Gb/2kb ~= 500 000
So you can host about 500 000 users on that 1 Gb
Assuming 2 byte characters like UTF-8 you can host about 250 000 users on that 1 Gb
Generally speaking, if you're not facebook or twitter or anything in that order of magnitude, 1Gb for a database (provided you won't use it story binary data such as images) is A LOT!