Twitter came under fire this week for a slowing growth rate, with industry watchers citing concern that lower-than-expected growth numbers released in its earnings report  could put the social networking site  in a vulnerable position a few years down the road.

Twitter’s executives, however,  are trying to convince investors that its reach far surpasses the number of people who visit the Twitter website or app; rather, they argue, official measures of reach should include tweets embedded on other websites, whether BuzzFeed or The New York Times or mobile ads delivered by MoPub, a mobile advertising company Twitter acquired in 2013.

On Tuesday, the company said it would begin displaying its “promoted tweets” on outside news sites or apps, giving advertisers a chance to reach a wider audience. The company also announced this week a new partnership with Google that will make the hundreds of millions of tweets that flow through the service every day much easier to find.

The question is, how much does reach matter? Twitter is already a staple of ad and PR activity — one need look no further than the recent Super Bowl (examples: Coke’s “Make It Happy” ad, which strives to fight against online bullying by changing the messages  to happy ones. Anyone who uses the hashtag #MakeItHappy with a negative comment they’ve received will get a personalized tweeted picture from Coke). It’s not just the big brands who will be affected by changes underway at Twitter — smaller businesses benefit from Twitter too by using the platform to connect with existing and new customers and drive word-of-mouth communication about their business.

But how do you measure success? About one-third of marketers report using Twitter to successfully generate leads.  but audience appeal varies widely by industry. According to a 2014 study, retailers and restaurants are the most engaging industries on Twtitter; apparel brands are the least engaging.

It’s worth examining how you are using social media.  Twitter and other social media networks can eat up a surprising amount of time and resources for a business of any size. With about half of people who log on to Twitter each month reportedly lurking, rather than posting, how can a business consistently measure the effectiveness of its Twitter activity?

How do you use Twitter? And how do you measure your success?