docs: Add description about what gluon is (freifunk-gluon#3035)

README.md

@@ -8,6 +8,34 @@ Gluon is a firmware framework to build preconfigured OpenWrt images for public m
 
 ## Getting started
 
+Gluon provides an easy-to-use firmware for a public, decentral WLAN and/or wire based mesh network.
+Common network capable devices, like smartphones, laptops or desktop PCs can connect to the mesh network and communicate over it, without the need of passwords for access and without the need of installing special software.
+Additionally, internet access and [merging mesh clouds](https://www.open-mesh.org/projects/batman-adv/wiki/Connecting-Batman-adv-clouds) can be accomplished over a WAN through VPN connected gateways.
+
+Gluon's features include:
+
+* a decentral mesh network
+* easy configuration mode for less techy users
+* community-specific technical settings and customizations through a common site.conf and site.mk
+* ecdsa signature-based autoupdater
+* node status web page
+* publication of node information + statistics through respondd
+* a variety of preconfigured mesh and VPN protocols:
+
+
+Supported mesh protocols:
+
+* batman-adv (BATMAN IV fully, BATMAN V partially)
+* OLSRv2 (partially)
+
+
+Supported protocols for node-to-node connections:
+
+* WLAN: 802.11s (with forwarding disabled)
+* WAN: VPNs via fastd and Wireguard
+* LAN: via VXLAN
+
+
 We have a huge amount of documentation over at https://gluon.readthedocs.io/.
 
 If you're new to Gluon and ready to get your feet wet, have a look at the