Today's Tech: New Google Nexus 7 specs, release date, hands-on, iPad mini spec comparison and Obama survives first Prism vote

Facebook has posted strong second-quarter earnings, with revenue of $1.81 billion (£1.2 billion), the majority of which was from advertising. Revenue was up 53 per cent from the same time period last year, Facebook said, and up from $1.46 billion (£938.9 million) last quarter. Earnings landed at $333 million (£217 million), which was up from $219 million (£142.7 million) last quarter and the $157 million (£102.2 million) loss it posted last year. Revenue from advertising was at $1.6 billion (£1 billion), or 88 per cent of total revenue, and up 61 per cent from last year. About 41 per cent of advertising revenue came from mobile ads. During a conference call with analysts, COO Sheryl Sandberg said that while Facebook now has one million active advertisers, that's "just a small fraction of the local businesses on Facebook, so this remains a larger growth opportunity for us." Facebook had 699 million daily active users as of June, up 27 per cent from last year. Monthly active users were at 1.16 billion, up 21 per cent from 2012. About 469 million people check Facebook from mobile devices on a daily basis, and 819 million do so every month.

Sainsbury's is hustling to keep pace with bitter rival Tesco, announcing a new low-cost mobile network intended to go toe-to-toe with Tesco Mobile. Mobile by Sainsbury's is being established in partnership with Vodafone and will concentrate on affordable pre-pay packages that it hopes will appeal to families. The network features three basic bundles: £10 a month gets you 200 minutes, and 250MB of data, £15 ups the game to 300 minutes and 500GB of data, while £20 gets you 800 minutes and 1GB of data. All packages come with unlimited texts. A range of devices will offered, starting at just £12 for the Nokia 100 and going up to £115 for the Nokia Lumia 520 or £109 for the Samsung Galaxy Fame. As part of the initiative, Sainsbury's will also be trialling in-store phone shops at six of its locations. Mobile by Sainsbury's will link up with users' Nectar cards to add to loyalty rewards, and the supermarket chain says that shoppers opting to switching to the network could end up nearly £200 better off. An über-basic plan is also available where users only pay for what they use - 8p a minute for calls, 4p per text, and 50p for 25MB of data per day.

Barack Obama has survived the first congressional challenge to the NSA's blanket collection of US phone records by a narrow margin. An introduced amendment aimed at curbing the NSA's indiscriminate collection of mobile phone records and metadata was defeated by the US House of Representatives in a 205-217 vote. The new legislation would have prevented further funding for the programme unless the NSA could prove that data collection was needed for a specific investigation, effectively ending the indiscriminate practice. The tight outcome does however show the Obama administration that there is a high level of disquiet over the surveillance programme in Congress, especially amongst his own party ranks. Michigan's Republican representative, Justin Amash, said he introduced the amendment to the annual Defense Department appropriations bill to "defend the fourth amendment, to defend the privacy of each and every American". Amash also cautioned that opponents to the proposals would, "Use the same tactic every government throughout history has used to justify its violation of rights: fear. They'll tell you that the government must violate the rights of the American people to protect us against those who hate our freedom."

Finally, in case you've been hiding away from the Internet and the news, Google launched the second version of its Nexus 7 tablet yesterday, and it has captured most of the world's attention. Today was a day filled with everything Nexus, from opinions, to specs, to release dates. We now have everything you need to know. The 16GB model will cost £199, the 32GB Wi-Fi only model will cost £239 and the 32GB 4G tablet will cost £299. It will land on UK shores from 13 September. We managed to get our hands on the device, following yesterday's big launch, and it made for an interesting experience. We've also compared the new Nexus 7 with the iPad mini, so you've got plenty of tech to get your teeth stuck into.