Try wrapping the features in the following:
{"type":"FeatureCollection","features":[
****ALL THE DATA HERE -- COMMA SEPARATED****
]}
and separating each feature with a comma.
For example, here's the first two features from the IE dataset:
{"geometry": {"type": "Point", "coordinates": [-6.422587, 53.293363]}, "type": "Feature", "id": "SG_41u80gC4971D4Gc0Fv1p8q_53.293363_-6.422587@1308163237", "properties": {"website": "http://www.buongiorno.com", "city": "Dublin", "name": "Buongiorno", "tags": ["mobile", "vas", "community", "social-networking", "connected-devices", "android", "tablets", "smartphones"], "country": "IE", "classifiers": [{"category": "Professional", "type": "Services", "subcategory": "Computer Services"}], "href": "http://api.simplegeo.com/1.0/features/SG_41u80gC4971D4Gc0Fv1p8q_53.293363_-6.422587@1308163237.json", "address": "Lake Drive City West Digital Park", "owner": "simplegeo", "postcode": "3050"}}
{"geometry": {"type": "Point", "coordinates": [-6.250848, 53.339347]}, "type": "Feature", "id": "SG_1dnWbWIg8hX3VyfUKIDRz9_53.339347_-6.250848@1308163237", "properties": {"website": "http://www.simchronise.com", "city": "Dublin", "name": "SIMchronise", "tags": ["mobile-solutions", "mobile-data", "data-synchronisation", "mobile-security", "backup", "restore", "mobile-contacts", "web-2.0-addressbook", "phonebackup"], "country": "IE", "classifiers": [{"category": "Professional", "type": "Services", "subcategory": "Computer Services"}], "href": "http://api.simplegeo.com/1.0/features/SG_1dnWbWIg8hX3VyfUKIDRz9_53.339347_-6.250848@1308163237.json", "address": "78 Merrion Square", "owner": "simplegeo", "postcode": "Dublin2"}}
... and here they are as a GeoJSON FeatureCollection:
{"type":"FeatureCollection","features":[
{"geometry": {"type": "Point", "coordinates": [-6.422587, 53.293363]}, "type": "Feature", "id": "SG_41u80gC4971D4Gc0Fv1p8q_53.293363_-6.422587@1308163237", "properties": {"website": "http://www.buongiorno.com", "city": "Dublin", "name": "Buongiorno", "tags": ["mobile", "vas", "community", "social-networking", "connected-devices", "android", "tablets", "smartphones"], "country": "IE", "classifiers": [{"category": "Professional", "type": "Services", "subcategory": "Computer Services"}], "href": "http://api.simplegeo.com/1.0/features/SG_41u80gC4971D4Gc0Fv1p8q_53.293363_-6.422587@1308163237.json", "address": "Lake Drive City West Digital Park", "owner": "simplegeo", "postcode": "3050"}},
{"geometry": {"type": "Point", "coordinates": [-6.250848, 53.339347]}, "type": "Feature", "id": "SG_1dnWbWIg8hX3VyfUKIDRz9_53.339347_-6.250848@1308163237", "properties": {"website": "http://www.simchronise.com", "city": "Dublin", "name": "SIMchronise", "tags": ["mobile-solutions", "mobile-data", "data-synchronisation", "mobile-security", "backup", "restore", "mobile-contacts", "web-2.0-addressbook", "phonebackup"], "country": "IE", "classifiers": [{"category": "Professional", "type": "Services", "subcategory": "Computer Services"}], "href": "http://api.simplegeo.com/1.0/features/SG_1dnWbWIg8hX3VyfUKIDRz9_53.339347_-6.250848@1308163237.json", "address": "78 Merrion Square", "owner": "simplegeo", "postcode": "Dublin2"}}
]}
Best Answer
Forewarning: given the amout of memory you are reporting on your system I suppose you are using a 64 bit build of Windows. If not this solution does not apply.
The memory limit for all 32 bit applications on Windows (regardless of the Windows version, so it is true also for 64 bit Windows) is 2GB. You might be hitting that limit, to confirm run ogr2ogr and check memory usage with task manager.
If the problem is indeed due to a memory issue you can do two things:
build yourself a 64 bit version of GDAL (I could not find readily avail binaries)
patch ogr2ogr.exe with this tool: http://ntcore.com/4gb_patch.php. After patching (make a backup copy of course) the binary should be available to address a grandtotal 4GB