Forums, groups,newsgroups etc always have ups and downs of participation based on various factors..time of year,holidays,people leaving and joining etc. and certainly things like Facebook also have an affect on this. But I still say that participation here, and in other Yahoo groups have been negatively affected due to the changes in u/ I by Yahoo...and that participation has really dropped off even more recently because of increased business by Yahoo. Look at the calendar of the front-page ...the monthly numbers started to drop in 2010 when Yahoo tried their first revamp of the u/I for the groups and then had to roll it back due to world-wide demand by users and advertisers. But the real drop-off in participation was in 2012-13 when Yahoo rolled out the new NEO interface for all the groups worldwide...people really hated and still hate the new u/I and started dropping out ...the numbers on the calendar tell the story. Now the increasing problems that people are having logging-in,posting and reading just added to the issues.
Just my 2-cents worth.
Cheers
Gene
