Homejoy and Exec are the perfect examples of companies that have gone very deep into their one offering, house cleaning. While other companies like Thumbtack and MyTime have gone very wide to gain more marketshare, faster. MyTime and Thumbtack offer every service under the sun. They are creating demand and then finding supply as they go. I am not sure if one strategy is better than the other when it comes to creating a marketplace for services website.
I think there are great lessons to be learned from Exec. They started out wide, but have gone very deep on cleaning.
It depends on the core thesis of your vision. Do you have a different product experience that could be competitive to existing marketplaces? Or are you just going for land-grab?
The most important thing to understand about the services marketplace business is that it's a very localized business operation.
I believe that if you're just looking to make money, the best way to do this is to go to "secondary markets" and build up marketplaces with a plan to sell to someone who has already raised great VC and has a presence in the major markets.
If you are looking to compete in major market cities, then the safer bet is to find the very deep opportunity unless you really believe your customer experience can beat the established players.
Happy to talk this through with you in more detail.
Thinking of a new venture (either startup or a new initiative within a larger company), I would always suggest being focused on a single offering first, but with the following caveats:
1. In my view, the purpose of the first offering is to test the business hypothesis, this means not only offering but: target audience, need, specifics of the offering as the solution, and its differentiation. Really be laser-focused on all of these.
2. The only way to test that complete hypothesis is to develop, in full, an offering for a well-defined target audience, etc.
3. Once it is out and you measure adoption and success, it's critical to assess which of the assumptions are proven to be valid - could be that the need is not strong for this audience, or that there's not enough differentiation - the offering is only a part of it. You can only test this well if you developed a good offering to a well-defined audience solving a well-defined problem.
4. Then - iterate. You may need to change your offering, but you may also discover that your audience has a stronger need (they all email you and ask for it). The key here is "drop" everything and be flexible - now it is time to lose the former focus - you may need to make dramatic changes.
In my experience, companies that went through this cycle (of building a deep offering and then iterating based on the data it provides) have been the most successful.
Depends on your business model.
If you search you'll find examples of businesses that have had success with both of those models (and if you are starting with a "preference" for one or the other - beware of confirmation bias).
Your question also states that you are after "more market share, faster." Another caution is to beware of vanity numbers and lack of specificity.
If you've mapped out a good business model you'll know your numbers (projected margins, cost of acquisition, break-even points) - and instead of using vague qualitative words like "more" and "faster" you will have targets that you can track and key metrics to measure.
If you are interested in how to quickly map out a business model perhaps we should talk. In any case - Best of Luck!