Bitcoin mining pool BTC Guild has just announced their intention to cease operations no later than June 30, 2015. This was announced by eleuthria on tardstalk, where all dead and soon-to-be-dead businesses go to announce "official" news.
Once in control of some 30% of the Bitcoin network's hashrate, BTC Guild is currently struggling to maintain even 2% of the network according to blockchain.info. This waning relevancy can be attributed not only to the competitive nature of Bitcoin mining, but also to BTC Guild's whole-hearted adoption of Mike Hearn and Gavin Andresen's 2013 hardfork at blockchain height 225,430. The fallout of that critical event in Bitcoin's history was to reveal the malicious intentions of Hearn and Andresen towards the vitality of Bitcoin1 and to sink the ship of any and all of their co-conspirators. Naturally enough, eleuthria didn't blame his own personal failings for, well, his own personal failings, he blamed "declining luck" in addition to the watered-down and nigh-on-irrelevant NYDFS BitLisence. Needless to say, Bitcoin can now bid adieu to another scab that signed the papers.
As a replacement service, eleuthria has recommended that miners direct their hashpower towards either BitMinter, Eligius, Kano CK Pool, or P2Pool. While Qntra doesn't formally recommend any mining pool in particular, neither is there any evidence that these suggested pools are inclined to submit as humbly and willingly to the pretenders of the ancien regime fiat.
Users holding funds with BTC Guild have until September 30, 2015 to request withdrawals.