Can I see what search terms drive traffic to competitor websites?

Yes. A competitor analysis tool shows the terms a competitor's pages rank for, which is a good proxy for where their search traffic comes from. Sohocheq lists the keywords each competitor wins and which specific pages own them, so you can see the topics bringing them visitors.

Is "ranks for" the same as "gets traffic from"?

Not exactly, but it's the closest signal you can measure from outside. A page ranking on page one for a term is getting some traffic from it. How much depends on the term's volume — which is why ranking data plus your own judgment about the topic is usually enough to decide whether it's worth chasing.

What about paid traffic?

Different signal. Paid traffic comes from ads, and the terms competitors bid on aren't visible from public ranking data. If you want to see what they're advertising on, you need a separate tool that tracks ad placements.

Which competitors can I compare?

Sohocheq compares 1 competitor per site on Premium, 3 on Pro, and 5 on Agency. The comparison shows which terms each competitor ranks for, and which terms multiple competitors own — those are the strongest signals because the demand is being met by more than one site.