Apple has acquired social media analytics firm Topsy for more than $200 million, The Wall Street Journal reported Monday.

The newspaper, citing sources familiar with the deal, said it was unclear how Apple planned to use the firm but that it could be related to Apple's new streaming music service.

Apple did not specifically comment on the report, but a spokeswoman said in a statement: "Apple buys smaller technology companies from time to time, and we generally do not discuss our purpose or plans."

Topsy, according to the report, is among a handful of Twitter partners which has access to the full range of data from the fast-growing messaging platform.

Earlier this year, Topsy said it had created a searchable index of all the publicly available tweets ever made, to be available for marketers and others.

Topsy did not respond to a request for comment.

Topsy describes itself as a company "with the only full-scale index of the public social web," to help its customers "instantly analyze any topic, term or hashtag across years of conversations on millions of web sites."

The data can be used to analyze the effectiveness of a social media ad campaign, for example.

Danny Sullivan, analyst at Search Engine Land, said Topsy "is about the only decent third-party Twitter search service to have survived, in recent years."

"Topsy's access to Twitter's 'firehose' of tweets and focus on providing search results and analytical tools make it even more robust than Twitter's own Twitter Search, for some queries," Sullivan said in a blog post.

But Sullivan said it's not clear if Twitter will continue to give Topsy "a sweetheart deal" for access under Apple's ownership. He said that Topsy had become "the definitive Twitter search engine" and was likely sought by Twitter itself.

Apple had a music-oriented social network called Ping, but shuttered that last year as it created sharing options through Facebook and Twitter.