Through a series of commits this week, Apache was ejected from the OpenBSD base build. The main reason for this was over Apache HTTPD being too bloated and this security-oriented BSD distribution instead suggesting that users/administrators switch to something lighter-weight like NGINX. NGINX along with lighttpd are lighter-weight alternatives known for their speed but also delivering a feature-set that's sufficient for most users. With the bloat/weight of modern Apache, its large code-base makes it more suspect to more security vulnerabilities that frightens OpenBSD stakeholders and its performance is no longer the jewel that it once was for web servers.
In addition to supporting HTTP/HTTPS, NGINX also can handle SMTP, POP3, and IMAP protocols. NGINX also boasts features like load balancing, HTTP caching, a reverse proxy with caching, IPv6 support, SPDY support, and other advanced features while being highly concurrent. NGINX is used these days by many high profile web-sites.
OpenBSD isn't the only one going ahead and pushing NGINX as a viable alternative to Apache but just this week as well NGINX-core made it into Ubuntu 14.04's main archive meaning it will be officially supported for this next Ubuntu Linux Long-Term Support release (except the extra/third-party modules were not added to main).
More details for OpenBSD administrators on removing Apache from base can be found via this OpenBSD web post. So far the responses seem positive amongst OpenBSD users for NGINX effectively replacing Apache.