Lately, I've been fortunate to attend some excellent training with Internet search gurus Phil Bradleyand Karen Blakeman. Here are some of my learning points, specifically about statistical information on the web, from those sessions.
OffStats http://www.offstats.auckland.ac.nz/ - a database of free, official statistics available to search by topic, country or region. Expertly compiled by the Business and Economics Information Services Team of the University of Auckland. Save time in locating the official sources of information, especially lesser known or less obvious sources. The regional collections could also serve as a reminder of wider scale comparative statistics and their originating organisations.
NationMaster.com is a similar service although there are some concerns about the frequency of updates. When I checked today (1 April 2015) the latest updates appear to date from 1 January 2015. Nevertheless a useful directory of statistical sources which provides useful clues to the publishers of information. These can then be checked independently. NationMaster also comes with some interesting data visualisation tools which may help to indicate trends, interesting features or anomalies and most importantly, missing data. In the example below, for steel production, the United Kingdom is missing from the dataset. This is odd because while the EU is listed, France, Germany and Spain have their own listings.
Google Public Data Explorer - A tool aggregating data from 136 sources including the likes of EuroStat, allowing data selection and visualisation. An interesting concept because there seems to be an expectation, in part, that developers will load their own choices of statistical data and make this available with graphics and visualisations. There don't appear to have been that many uploads of this type but if the data that you are looking for is given then you will be rewarded with some great visuals and interesting features. Google Public Data
Other information sources?
Guardian data blog - potentially interesting if it includes information that you are looking for. One to check quickly using Google Advanced searching and the site:http://www.theguardian.com/data option. Original postings at Guardian Datablog
Don't forget data.gov.uk and StatsWales. Again, advanced searching techniques might be required to find the information required. These are complex data sets. There may be missing data, and occasionally data errors (e.g. Keying errors, unwanted spaces, incorrect decimal points, etc).
Zanran - the numerical search engine, searches for data from charts, tables and images. Zanran. Provides a vast array of answers, but filters can be used to narrow search results. Data sources may need confirming / double checking. Annoyingly free registration is required to access to original result in full text. If other statistical sources fail then Zanran may be a useful resource especially as this may select data from slide presentations, reports and materials containing tabular information.
Statista.com - a subscription site although some basic information may be available free of charge. Registration with this site is required to access full statistical information. Statista.com
Wolfram Alpha may also be a potential source for factual data. Wolfram Alpha
I'll be interested to know if you recommend any other sources! Please do comment below.