Ansovino
Image Credit: Ricardo Gomez Angel
2019 · Manage your farm better with Ansovino. Receive email and SMS alerts when measured or forecasted weather, climate values or indices, cattle comfort and heat stress surpass or drop below pre-set thresholds in your fields. This helps adjusting planting, transplanting and harvesting times, protecting fruit trees from frost damage, or planning pest management activities. Sentinel-2 satellite data, EVI and NDVI maps help monitoring crop vigor and vegetation cover. Schedule spraying operations during favorable weather conditions.
PPKG
2016 · Family farm and bootstrapped agritech company. Ansovino.eu, its flagship service allows monitoring weather, climate, cattle comfort, soil measurements and forecasts for small-holder farmers around the world.
IPCim.com
2007 · This site was initially created as a (fairly successful) search engine optimization experiment for the term „IP cím”, or „IP address” in Hungarian, with the simple function of showing the IP address and host name of the visitor’s computer. Later a few more features have been added: geolocation based on the client’s IP address, optimized templates for mobile devices in HTML5 and WAP/WML (I know), and a simple speed test.
Lessons learned: Smarty PHP templating engine, user agent based template switching, Maxmind.com’s GeoIP City web service, Google Maps API, search engine optimization, WML.
Mirino
2014 · Mirino.eu is a minimal weather service for over 60 000 cities in Europe. Its main focus is to provide a simple, fast, device and resolution independent overview of the current weather conditions, an hourly forecast for the next 48 hours and a 9-day forecast in English, German, French, Italian, Polish and Hungarian.
Lessons learned: Dark Sky, OpenWeather and 
Weather APIs, GeoNames
geographical database, SVG in HTML5, hCalendar structured data.
Mars Panoramas
Image Credit: NASA/JPL-Caltech/Cornell University
2006 · Google Maps offers a number of interesting technologies – satellite imagery, geocoding, driving directions, data overlays – and a free API to play with. The near-cylindric projection used by Google for their map images gave the idea to create interactive images from large panoramas that can be zoomed seamlessly. This experiment uses some of the best panoramic photos acquired by NASA’s Phoenix lander, Mars Pathfinder, Spirit and Opportunity rovers on the planet Mars.
Lessons learned: Google Maps Javascript API v2 and v3, Leaflet.js, map tile generation with PHP and GD, XHTML 1.0 Strict and HTML5.
ECDL.web
2006–2018 · The first texts that later became ECDLweb.hu and its English language counterpart originated in the late 1990s when I wrote educational materials for ECDL (European Computer Driving Licence) courses, first discussing Windows 2000, Microsoft Office 97 and Netscape 4.5, then updated to Office 2000, 2003 and Windows XP. ECDL, which is known as the International Computer Driving Licence (ICDL) outside Europe, is a global, modular standard in end-user computer skills certification. With no comparable material available in Hungarian for free, I have put it online in plain HTML format first, and a few years later converted to a wiki and moved to its own domain.
Lessons learned: MediaWiki installation, configuration, editing; anti-spam MediaWiki extensions, search engine optimization, KML generation, KML layers on Google Maps.
Google News Treemap
2008 · The latest news visualized as a treemap using RSS feeds from Google News. In this visualization the more sources a news story has the more visible it becomes.
Lessons learned: Magpie RSS parser, HTML treemap generation.
Textlink.hu
2011–2018 · Textlink.hu was a simple web page directory, a Hungarian language subset of the Open Directory Project. It features website thumbnails, search engine statistics, HTML validation, metadata extraction and web server information.
Lessons learned: DMoz RDF XML, Google Charts API, Google and Yahoo! search engine statistics, IECapt, Amazon S3 and CloudFront.