The best thing is to go public only when you're absolutely sure that's the right move for the company. And in order to make sure that is the case, you need to have as much control over the company as possible, which means not giving up control early on.
I hadn't really worked in an office before Shutterstock, so I didn't have the experience of building a culture, nor did I understand how important that is for attracting and retaining the best talent.
The best ways of marketing were email and banner advertising, but I needed images... and they were very expensive.