@Ryanl, I wouldn't. Not so much because of rankings concerns, but because the conversion funnel is so messy. Most people will go to the site, rather than call the number on your HA or Yelp or other listing. Also, some people's searches may end on a review site, particularly on Yelp: they found you somewhere else, were leaning toward calling you, and only decided to call you after reading your reviews on this site or that site.
I'd focus on tracking online conversions, and maybe put DNI tracking numbers on the site.
I'm with Phil on this, with one exception. If you're paying a decent amount of money for paid placement on a site, then it might be worth it to use a call tracking number to be able to measure the value of that spend.
The one example I saw where this make sense was a legal client that was paying AVVO thousands per month to have a paid/promoted listing on top of all the other lawyers in their category. They used a call tracking number on their avvo listing, and it was helpful, because they discovered that they were DEFINITELY getting a great return on that investment in terms of leads that called and closed.
To Phil's point, a few different numbers across the local search ecosystem shouldn't hurt your rankings. I wouldn't put them on any sites that distribute to other sites, though, because then the number will spread, and it will mess up your attribution data.
@Ryanl, good advice from Darren, including that exception. It's good to have that directory-specific call-tracking number (in addition to other tracking) to determine whether the paid placement is good ROI. Can be, as Darren mentioned. Or it may be a waste. I once helped one of my attorney clients save a chunk by determining that Avvo wasn't worth paying for in his case.
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