Most online casinos deal only one hand before shuffling. A few will deal something like 10% of the shoe before dealing, but they will be using 6 or 8 decks, not single deck.
I doubt that there are any places that an advantage could be gained at by counting.
Thats said, I believe that Pharoah's single deck is an advantageous game to start with; Ken did a 10 day 'experiement' there which he blogged. Use the search feature for this site and looked for 'pharoah's'.