I have seen that many job postings, including many on Stack Overflow Careers, in the "salary" section write "provides equity".
What does it mean, in the context of salary/compensation?
It means that you will get shares in the company as part of your contract, either standard, or as part of your bonus.
It usually happens with startups (also bigger US companies).
These are taxed lower since you bear the risk of getting less money should the company go belly-up.