diff --git a/README.md b/README.md
index d50b614..c631d5e 100644
--- a/README.md
+++ b/README.md
@@ -1,16 +1,52 @@
-**libravatarserv** is a simple [libravatar](https://wiki.libravatar.org/)
-server. It is intended as a
+**libravatarserv** is a simple [libravatar](https://www.libravatar.org/) server.
+It is intended as a
 [CGI](https://en.wikipedia.org/wiki/Common_Gateway_Interface) program.
 
+Libravatar is a free service and an open specification for hosting profile
+images tied to email or OpenID addresses.
+
+## Features
+
+* Avatar delivery based on email addresses
+* Default avatar for unknown addresses
+* MD5 hashes
+* SHA256 hashes
+
+### Soon
+
+* Variable image size (`s`)
+
+### Not supported
+
+* Avatar delivery based on OpenID
+* Default URL for missing images (`d`)
+
 ## Usage
 
+Install nginx and
+[fcgiwrap](https://www.nginx.com/resources/wiki/start/topics/examples/fcgiwrap/),
+copy the [example config](https://schlomp.space/tastytea/libravatarserv/src/branch/master/doc/nginx-example.conf) to the nginx configuration directory and edit it
+according to your needs. Other webservers and cgi spawners will also work, of
+course.
+
+libravatarserv looks in each of `${XDG_DATA_DIRS}` for a directory named
+`libravatarserv`. You can force a different directory by setting the environment
+variable `${AVATAR_DIR}`.
+
+The image files are named like your email address, no file extension. Example:
+`user@example.com`. If you want to deliver a default image for unknown email
+addresses, name it `default`.
+
 ## Install
 
 ### Dependencies
 
-* C++ compiler (tested: [gcc](https://gcc.gnu.org/) 6/7/8,
-  [clang](https://llvm.org/) 3/5/6)
+* C++ compiler (tested: [gcc](https://gcc.gnu.org/) 7,
+  [clang](https://llvm.org/) 6)
 * [cmake](https://cmake.org/) (at least 3.2)
+* [crypto++](https://cryptopp.com) (tested: 7.0)
+* [imagemagick](https://www.imagemagick.org/) (tested: 7.0)
+* [libxdg-basedir](http://repo.or.cz/w/libxdg-basedir.git) (tested: 1.2)
 
 ### Compile
 
@@ -27,6 +63,10 @@ make install
 Contributions are always welcome. You can submit them as pull requests or via
 email to `tastytea`@`tastytea.de`.
 
+## Contact
+
+See https://tastytea.de/
+
 ## License & Copyright
 
 ```PLAIN