[joshtronic]

Titles are pretty meaningless in most startup scenarios. It sounds more like they are looking for a technical co-founder and are using the C-level title as a carrot.

If there is not a team already in place, you will most likely be handling the early programming efforts until a team takes shape.

That's assuming a team ever does take shape. Depending on the vision of the other founders (and funding / budget), you may end up being the entire team. The title will look good on your resume but I wouldn't take it all that literally in regard to your day-to-day responsibilities.

Regarding how it may change over time, it very well could be a vanity title until another person is installed in the position over you. That's not always the case, but I've seen it happen. If you are given the opportunity to grow a team and play an active role in the technical vision of the company (assuming you're allowed to) you will probably grow with the position.

Source: Former "CTO" at two startups.