Board Thread:Questions and Answers/@comment-37.26.147.229-20180317115127/@comment-6697950-20180317115538

No one "connected" ALO with SAO. ALO is a game running on a copy of SAO's server, hence assets from SAO are available on the ALO server. When ALO was sold to a new company (Ymir), their employees found said SAO assets, including Aincrad, and decided to incorporate them into ALO. Same goes for SAO avatars - players were allowed to import their SAO avatars to ALO, hence why the main cast looks a lot like their real life/SAO selves, aside from minor changes like different hair colour.